Add Warm-Up and Stretching activity types

Adds WorkoutActivityType.warmUp (HealthKit .preparationAndRecovery) and
.stretching (.flexibility), and retags the six starter splits that were all
mislabeled as Functional Strength:

- Warm-Up:    Upper Body Warm-Up, Lower Body Warm-Up, Morning Wake-Up
- Stretching: Morning Mobility, Full Body Stretch, Evening Stretch

The split editor's activity picker surfaces them automatically (CaseIterable).
Older app versions decode the new raw values as the default type — additive and
not schema-gated, so no quarantine.

Exercise Library/Dip/frames/frame-2.svg

@@ -1,15 +1,32 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Dip</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="164.6" y1="124.5" x2="195.7" y2="142.2"><stop offset="0" stop-color="#9ea4af"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+  </defs>
   <path d="M 137.7 158.7 L 207.6 158.7 L 207.6 150.6 L 137.7 150.6 Z" fill="none" stroke="#b9bec9" stroke-width="2.34" stroke-linejoin="round"/>
   <path d="M 172.5 84.9 L 172.5 150.4" stroke="#c5cad4" stroke-width="3.9000000000000004" stroke-linecap="round" stroke-linejoin="round"/>
   <circle cx="172.5" cy="81.0" r="2.73" fill="#6b7180"/>
-  <path id="leg_l" d="M 164.6 124.5 L 195.7 142.2 L 164.5 143.2 L 161.8 151.3" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 187.2 62.6 L 164.0 60.2 L 174.0 81.0" stroke="#86cfc5" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 124.9 L 191.1 142.5 L 159.9 143.6 L 157.2 151.6" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.6 124.5 L 195.7 142.2" stroke="url(#grad-leg_l-0)" stroke-width="3.93834" stroke-linecap="round"/>
+    <path d="M 195.7 142.2 L 164.5 143.2" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round"/>
+    <path d="M 164.5 143.2 L 161.8 151.3" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 187.2 62.6 L 164.0 60.2" stroke="#86cfc5" stroke-width="3.9" stroke-linecap="round"/>
+    <path d="M 164.0 60.2 L 174.0 81.0" stroke="#86cfc5" stroke-width="3.9" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 124.9 L 191.1 142.5" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 191.1 142.5 L 159.9 143.6" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 159.9 143.6 L 157.2 151.6" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 187.2 62.6 L 182.6 62.6 L 182.6 64.1" stroke="#3a3f4b" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 164.6 124.5 L 160.0 123.9 L 160.0 124.9" stroke="#3a3f4b" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 123.9 Q 169.4 91.8 182.6 62.6" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 182.6 64.1 L 159.3 62.4 L 170.9 82.4" stroke="#0d9488" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 182.6 64.1 L 159.3 62.4" stroke="#0d9488" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 159.3 62.4 L 170.9 82.4" stroke="#0d9488" stroke-width="4.68" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="190.4" cy="49.3" r="7.800000000000001" fill="white" stroke="#3a3f4b" stroke-width="4.68"/>
   <line id="nose" x1="198.0" y1="51.3" x2="203.3" y2="52.7" stroke="#3a3f4b" stroke-width="3.12" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">